Abstract 3036: Is the Sympathetic Nervous System, Renin-angiotensin System and Cytokines Activated in Asymptomatic Patients with Chronic Organic Mitral Regurgitation and Normal Left Ventricular Functional Reserve?
Activation of the sympathetic nervous system, reninangiotensin system and cytokines has been observed in patients (pts) with congestive heart failure associated with chronic mitral regurgitation (MR). In order to further understand the pathophysiology of chronic MR, it is important to know whether these neurohormonal systems are activated in pts with chronic MR and normal LV function.
Methods: Twenty pts with chronic MR were studied. All the pts had mitral valve prolapse and moderately severe or severe MR with a mean regurgitant orifice area of 0.42 ± 0.05 cm2. Mean exercise capacity on the Bruce protocol was 12 ± 3 Mets. LV diameters and LVEF were measured at rest and immediately post exercise by echocardiography. Normal LV function was defined as resting LV ejection fraction (LVEF) of > 60 % with normal LV systolic functional reserve (increased LVEF of ≥ 5% post exercise). Plasma norepinephrine (NP), renin activity (RA) and tumor necrosis factor-alpha (TNF-α) were measured in pts with MR and 13 normal subjects without MR.
Results: LV end-diastolic diameter (5.4 ± 0.5 cm vs. 4.5 ± 0.5 cm, p<0.01) and end-systolic diameter (3.6 ± 0.6 cm vs. 2.6 ± 0.5 cm, p<0.01) were significantly larger in pts with MR than the normal subjects. Resting LVEF was similar in two groups (MR: 65 ± 4% vs. normal: 59 ± 6%, p>0.05). There were no significant differences in plasma NP, RA and TNF-α between the MR and normal groups (Table⇓). NP, RA and TNF-α were not significantly associated with exercise capacity, LV end-diastolic and systolic diameters and pre- and post-exercise LVEF (all p> 0.05).
Conclusion: Unlike pts with LV dysfunction and MR, neurohormones are not significantly activated in asymptomatic pts with chronic MR and normal LV systolic functional reserve. Therefore, elevation of the neurohormonal levels and/or reduced LV functional reserve may indicate LV function impairment and prompt early surgical and/or medical intervention.